Technical Field
The present invention relates to a communication system for performing communication between a vehicle such as an electric vehicle or a hybrid vehicle and a power feeding device for feeding power to the vehicle, and to a communication device constituting the communication system.
Description of Related Art
In recent years, environmental technology has increasingly attracted attentions as a technique for addressing global warming. Such environmental technology includes, for example, an electric vehicle or a hybrid vehicle, which has been put into practical use, with a motor employed as a drive unit instead of a conventional engine consuming gasoline.
A vehicle such as an electric vehicle or a hybrid vehicle described above has a structure in which a charge plug connected to an external power feeding device is further connected to a connector at a power feeding port provided on a vehicle so that a secondary battery may be charged from the outside of the vehicle.
An interface between a vehicle and a power feeding device (charging station) in feeding power to the vehicle has already been standardized. For example, a signal line called a control pilot line is provided between an output circuit located on the power feeding device side and an input circuit located on the vehicle side, a rectangular wave signal (control pilot signal) of a predetermined frequency is output from the output circuit to the input circuit, and a voltage level at a predetermined portion of the input circuit is changed, allowing both the power feeding device and the vehicle to recognize information on the charge state of the vehicle and the like (see SAE International (Society of Automotive Engineers International), SURFACE VEHICLE RECOMMENDED PRACTICE, 2010-01).
Meanwhile, such a communication system has also been discussed that is able to further perform transmission and reception of various kinds of information between the power feeding device and the vehicle by superimposing a communication signal onto a control pilot line.